CN111101130B

CN111101130B - Chemical extinction method

Info

Publication number: CN111101130B
Application number: CN201911029622.6A
Authority: CN
Inventors: 皮埃尔-约瑟夫·泽维尔·赫维·萨吉特
Original assignee: SNECMA SAS
Current assignee: Safran Aircraft Engines SAS
Priority date: 2018-10-26
Filing date: 2019-10-28
Publication date: 2023-07-04
Anticipated expiration: 2039-10-28
Also published as: EP3643812A1; US20200131646A1; EP3643812B1; US11280007B2; FR3087794B1; CN111101130A; FR3087794A1

Abstract

The invention relates to a chemical matting method, in particular for matting a turbine engine component (10) comprising a metallic material, comprising the step of immersing said component in a chemical bath (14) to matting said metallic component (10), the bath (14) comprising at least sodium fluoride (NaF) and Hydrofluoric (HF) acid, characterized in that the immersing step lasts from 2 minutes to 15 minutes.

Description

Chemical extinction method

Technical Field

The present invention relates to the general field of graphic measurement of turbine engine components, in particular to so-called CM non-contact measurement methods, in particular for preparing upstream components for these measurements.

Background

In the context of a program for producing turbine engines, in particular aircraft turbine engines, certain components into the composition of the turbine engines are mapped by non-contact measurements called "CM". Such a measurement is, for example, a so-called "optical" measurement, for example as described in document FR 2 961 598a 1. According to these methods, the measurements may take place at different production stages, in some cases when the component has not been completed. However, the unfinished parts may thus be too bright, especially due to various reflections and/or reflections, and the machine for implementing the CM method cannot obtain the data required for drawing. To enable these plots to be made at the stage of producing the desired turbine engine, the operator has matted these components.

Conventionally and in a manner known per se, this extinction is done manually in the tumbling slurry.

Tumbling (also known as mechanochemical polishing, friction finishing, or surface polishing (trowagging)) is a well-known method that allows the surface state and edges of components, particularly components made of metal, to be altered. The component is immersed in an abrasive mixture that moves in the reservoir by vibration, oscillation, and/or rotation. The results observed on the part are due to friction between the part and the abrasive mixture. The result depends on the type of equipment used, the composition of the abrasive mixture, the speed parameters, and the duration of the operation.

In the present case, the extinction of the turbine engine component to be mapped is accomplished by such tumbling mud. The slurry is recovered and then deposited by a brush on the part to be painted before measurement, then removed with cloth after CM measurement and possibly rinsed.

This method can affect the accuracy of the measurement due to the non-uniform extinction appearance of the part being mapped and the potentially present residue. In addition, this method requires a large number of repeated and difficult treatments, resulting in ergonomic problems, safety, health and environmental (SHE) problems, such as musculoskeletal trauma. With these treatments, this method results in a loss of time and is expensive.

Object of the Invention

The object of the present invention is to treat the parts to be painted to obtain a uniform matting, without potential residues, which is safer, cheaper than the prior art methods, and which can be achieved industrially.

Disclosure of Invention

The object according to the invention is achieved by a method for matting a turbine engine component comprising a metallic material, comprising the step of immersing said component in a bath comprising at least sodium fluoride (NaF) and Hydrofluoro (HF) acid for a period of 2 to 15 minutes to chemically matting said metallic component.

Thus, this chemical extinction solution makes it possible to achieve the above-mentioned object. In practice, uniform extinction is achieved by soaking or rinsing in the bath, which reduces the number of treatments and improves safety and reliability.

The method further includes one or more of the following features taken alone or in combination:

the soaking step is configured to dissolve the metallic material uniformly over a thickness of about 3 μm to 10 μm and enrich the component with a minimum amount of dihydro (H ₂ )，

The metallic material of the component comprises titanium (Ti), titanium alloy and/or titanium dioxide (TiO ₂ )，

The thickness of the dissolved material is 5 μm,

dihydro (H) of the component ₂ ) Is enriched to about 15ppm,

the component is obtained by a forging process and has titanium dioxide (TiO ₂ ) And an alpha shell layer, so that titanium dioxide (TiO ₂ ) And the alpha shell layer is removed,

homogeneous dissolution occurs sequentially and/or simultaneously according to two chemical reactions:

(1)NaF+H ₂ SO ₄ ＝FH+NaHSO ₄

(2)TiO ₂ +6HF→TiF ₆ H ₂ +H ₂ O，

the method comprises the following steps: before the step of immersing in the chemical bath, at least one component to be matted is mounted in the tool,

during the soaking step, the temperature of the chemical bath is between 15 ℃ and 30 ℃.

-the method comprises the steps of:

-a step of preparing a surface of at least one component, and

a step of rinsing the component(s),

-the step of preparing the surface of the component is performed before the soaking step and comprises:

a degreasing step of the component at a temperature of 45 ℃ to 55 ℃ for 10 minutes, during which the tool is immersed in an alkaline bath,

a first passive rinsing step, carried out at ambient temperature for 60 seconds, during which the tool is immersed in a bath of water,

a first flow-through (current) rinsing step at ambient temperature for 120 seconds, during which the tool is immersed in a jet of water or running water bath,

-a step of rinsing and then drying the parts coming from the same tool.

Drawings

The invention will be best understood and other objects, details, features and advantages thereof will become more apparent upon reading the following detailed illustrative description of an embodiment of the invention, given by way of illustrative and non-limiting example only, with reference to the accompanying schematic drawings in which fig. 1 shows a series of turbine engine components to be drawn according to the matting method according to the invention, aligned on a tool, ready to be immersed in a bath.

Detailed Description

The operating conditions of the turbine engine result in the use of a large number of metal components 10. In particular, some of these metal parts 10 are made of titanium (Ti) or an alloy containing titanium (Ti). Importantly, during the production of the turbine engine, these components 10 are subjected to non-destructive testing, which is used to highlight possible production defects. These parts 10 are typically obtained by forging methods and are very glossy after their assembly.

In addition, these components 10 have titanium dioxide (TiO ₂ ) And an alpha shell layer. This layer generally comes from any method for forging a component 10 comprising titanium (Ti). In metallurgy, the term "alpha shell" refers to an oxygen-rich surface phase that occurs when titanium or an alloy of titanium is exposed to air or high temperature oxygen. The phase is hard and brittle, tends to generate microcracks and impairs the performance of the metal part.

Thus, the present invention has the advantage of removing the various oxides and surface alpha layers of the part 10 while simultaneously matting the part 10 to be painted.

Thus, in fig. 1, a series of components 10 to be matted, which need to be drawn, can be seen. In the present case, these components are the leading edges of turbine engine components used to assemble, for example, a compressor wheel. These components 10 are secured to the tool 12 and aligned over the tool 12, the tool 12 being intended to be immersed in a series of different baths with the components 10.

During the installation of the components 10 on the tool 12 or the implementation of the components 10 on the tool 12, it must be verified that the components 10 are not in contact with each other, as this would prevent different baths from acting on the entire surface of each of the components 10. For this purpose, the tool can carry up to six parts to leave sufficient space between each part. Of course, the number of parts will depend on the size of the tool and the size of the container or reservoir used to hold the bath. It must also be verified that the tool 12 is in an operational state and that the tool 12 is clean. Furthermore, the etching of the numbering of the tool 12 must be clearly discernable in order to ensure good traceability of the components.

The tool also includes a dissolution conduit (not shown) that allows the extinction time to be determined. The conduit used is typically a metal conduit. The metal conduit is made of a TA6V titanium (Ti) alloy and has a rectangular shape herein.

Once the component 10 is properly secured to the tool 12 and in a good operating condition, the tool 12 is immersed in a first reservoir comprising an alkaline bath (e.g., a soda-based bath). This makes it possible to achieve degreasing of the component 10. This step of degreasing the component 10 lasts 10 minutes (with a tolerance of + -5 minutes). The temperature of the alkaline bath is 45 ℃ to 55 ℃.

The tool 12 with the component 10 is then immersed in a second tank comprising water. This makes it possible to perform a first step of rinsing (called passive rinsing) the degreased part 10.

Conventionally and in a manner known per se, passive rinsing (also referred to as static rinsing) refers to pre-rinsing, which serves to retain a portion of the contaminants from the treatment bath (here alkaline bath). The passive rinse bath is not continuously supplied with fresh water, but is replaced periodically. This may be a way to reduce the rejected pollution load if the bath is intended to treat special waste. Passive rinsing may also reduce the amount of rinsing water. For example, the passive rinse liquid that is drained when 20% of the treatment bath concentration is reached makes it possible to divide the amount of rinse water by 5, i.e. to save 80% of the water.

The first passive rinse step lasts about 60 seconds. This step is advantageously performed at ambient temperature.

The tool 12 with the component 10 is then immersed in a third tank, which also contains water. This makes it possible to perform a first rinsing step, called a flow-through rinsing step, i.e. to continuously supply fresh/tap water to the third tank. The first flow rinse lasts about 120 seconds. The flow-through rinsing is advantageously carried out at ambient temperature. This step may also be performed by spraying the tool 12.

Thus, the tool 12 and the component 10 are immersed in the fourth tank. The fourth reservoir further comprises a chemical bath 14 according to the invention. The step of treating the metal part is performed in the fourth tank. Strictly speaking, this treatment step is a chemical extinction step. To perform such extinction, the component is immersed in a chemical bath to achieve uniform dissolution of the metallic material. The soaking of the parts was continued for 2 to 15 minutes (with a tolerance of + -1 minute). The soaking step is carried out at a temperature of 15 ℃ to 30 ℃. In particular, the chemical bath reaches the temperature of 15 ℃ to 30 ℃.

In particular, the bath 14 of the soaking or treating step comprises sodium fluoride (NaF) in a ratio of 11g to 15g per liter of bath 14 and sulfuric acid (H) in a ratio of 75+ -5 mL per liter of bath 14 ₂ SO ₄ ) (density 1.83). The remainder of the bath 14 is water (H ₂ O) is completed. Sodium fluoride (NaF) release F in aqueous solution ^- Ion, and sulfuric acid (H) ₂ SO ₄ ) Production of H ⁺ Ions, which allow the formation of dilute Hydrofluoro (HF) acids. Thus, sodium fluoride (NaF) and sulfuric acid (H) ₂ SO ₄ ) React with each other according to the following reaction scheme:

-NaF+H ₂ SO ₄ ＝FH+NaHSO ₄ thus, hydrofluoric acid (HF) was obtained.

When titanium dioxide (TiO ₂ ) When the part 10 is immersed in the chemical bath 14, it is observed that the Hydrofluoro (HF) acid and the titanium dioxide (TiO ₂ ) The reaction occurs:

-TiO _2(S) +6HF ₍₁₎ →TiF ₆ H _2(s) +H ₂ O _(l) 。

wherein Ti is not present in the solution ⁴⁺ Ion, ti ⁴⁺ Ion quilt F ^- Ion complexation to specifically produce solid TiF ₆ H ₂ Solid state TiF ₆ H ₂ Is dissolved in the bath 14. The oxide of the surface of the components 10 is removed and thus the surface of each component 10 is uniformly cleaned/matted.

F ^- The ion converts titanium (Ti) to Ti by its complexing force ³⁺ Form and observing hydrogen (H) ₂ ) And releasing the gas. This hydrogen release enriches the matt surface of the component 10 with H by adsorption onto the surface and then permeation ⁺ Ions. In the case of the present invention, the dissolution of titanium (Ti) is weak, whereas the component 10 is not highly enriched in H ⁺ 。H ₂ Is limited to about 15ppm + -5 ppm.

The thickness of the dissolved layer is 3 μm to 10 μm. The thickness of the dissolved layer is preferably not more than 5 μm.

The time for treating the parts 10 was developed for each series of parts 10 in accordance with the glossiness of each series of parts 10 after assembly in order to sufficiently matt the parts 10 without consuming a dissolution thickness of not more than 5 μm. More specifically, the soaking step is configured to uniformly dissolve the metallic material of the component 10 over a thickness of about 3 μm to 10 μm. This configuration also ensures that the component 10 is enriched with a minimum amount of dihydro (H ₂ )。

After the treatment step, the tool 12 is immersed in a fifth tank. The reservoir contains water and allows a second passive rinsing step of about 60 seconds to be performed, which occurs at ambient temperature.

Thus, the tool 12 is immersed in a sixth tank containing moving water to perform a second flow-through rinsing step at ambient temperature for about 120 seconds. As with the previous flow-through rinsing step, this step may be performed by a water spray device.

Finally, the tool 12 and the component 10 are immersed in a seventh tank containing water at a temperature greater than or equal to 70 ℃ and forming a hot rinse bath. This hot rinse lasts 45 seconds.

After this last rinse, the part 10 is disconnected from the tool 14 and the part 10 is tested by the appropriate CM.

Furthermore, this solution makes it possible to obtain good measurement accuracy, since the appearance of extinction is uniform and the component is completely clean (no residues) for the measurement.

The solution is of course applicable to any type of component that can be fitted with any type of turbine engine.

According to the invention, the use of chemical baths instead of tumbling slurries to matt parts is of great economic interest: accident is reduced and analysis time is greatly shortened. In practice, the analysis time took about 3 hours from six parts to six parts for about 30 minutes.

Claims

1. A method for matting a turbine engine component (10) comprising a metallic material, the method comprising the step of immersing the turbine engine component in a chemical bath (14) to matting the turbine engine component (10), the chemical bath (14) comprising at least sodium fluoride and hydrofluoric acid, characterized in that the immersing step lasts from 2 minutes to 15 minutes.

2. The method according to claim 1, characterized in that the soaking step is configured to dissolve the metallic material uniformly over a thickness of 3 to 10 μm and enrich the turbine engine component (10) with dihydro.

3. The method according to claim 1 or 2, wherein the metallic material of the turbine engine component (10) comprises titanium, a titanium alloy and/or titanium dioxide.

4. A method according to claim 2, characterized in that the thickness of the dissolved metallic material is 5 μm.

5. The method of claim 2, wherein the turbine engine component (10) has an enrichment of 15ppm of dihydro.

6. The method of claim 2, wherein the turbine engine component (10) has titanium dioxide and an alpha shell on a surface, the uniform dissolution enabling removal of the titanium dioxide and the alpha shell.

7. The method according to claim 6, wherein the uniform dissolution occurs sequentially and/or simultaneously according to two chemical reactions:

（3） NaF + H ₂ SO ₄ = FH + NaHSO ₄

（4）TiO ₂ + 6HF → TiF ₆ H ₂ + H ₂ O。

8. a method according to claim 1 or 2, characterized in that the method comprises the steps of: at least one turbine engine component (10) to be delustered is installed in a tool (12) prior to the step of immersing in the chemical bath.

9. The method of claim 8, wherein the temperature of the chemical bath during the immersing step is between 15 ℃ and 30 ℃.

10. The method according to claim 9, characterized in that it comprises the steps of:

-a step of preparing a surface of the at least one turbine engine component (10), and

-a rinsing step of rinsing the turbine engine component (10).

11. The method according to claim 10, wherein the step of preparing the surface of the at least one turbine engine component (10) is performed before the immersing step and comprises:

subjecting the turbine engine component to a degreasing step at a temperature of 45 ℃ to 55 ℃ for 10 minutes, during which the tool is immersed in an alkaline bath,

a first passive rinsing step at ambient temperature for 60 seconds, during which the tool is immersed in a water bath,

-a first flow-through rinsing step at ambient temperature for 120 seconds, during which the tool is immersed in sprayed water or running water bath.

12. The method of claim 10, wherein the rinsing step is performed after the soaking step and comprises:

a second passive rinsing step at ambient temperature for 60 seconds, during which the tool (12) is immersed in a bath of water,

a second flow-through rinsing step carried out at ambient temperature for 120 seconds, during which the tool (12) is immersed in a jet of water or running water bath,

-a final hot rinsing step at a temperature of greater than or equal to 70 ℃ for 45 seconds, during which the tool (12) is immersed in a jet of water or running water bath.